Combination variable resistor and switching means

ABSTRACT

A variable resistor-switch combination comprising an electrical resistance path, electrical switch means integral with the electrical resistance path, and movable electrical contact means cooperating with the electrical resistance path and the electrical switch means.

[ Feb. 22, 1972 United States Patent Kirby et al.

[56] References Cited UNITED STATES PATENTS 2,929,040 3/1960 Barden et [54] COMBINATION VARIABLE RESISTOR AND SWITCHING MEANS [72] Inventors: Joseph L. Kirby, Thomtown; George 0.

Puemermnkfm' bmh 1,823,472 9/1931 Schellenger..........

[73] Assignee: P. R. Mallory & Co. Inc., Indianapolis,

Ind.

Primary ExaminerThomas J. Kozma Assistant Examiner-D. A. Tone [22] Filed: Nov. 4, 1970 [21] Appl.No.: 86,753

Attorney-Richard H. Childress, Robert F. Meyer and Henry W. Cummings ABSTRACT A variable resistor-switch combination comprising an electri- .338/l73, 338/178, 338/200 9/08 333 172 173 173 179 193 cal resistance path, electrical switch means integral with the 333/200 electrical resistance path, and movable electrical contact means cooperating with the electrical resistance path and the electrical switch means.

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7 Claims, 3 Drawing Figures PATENTEDFEBZZ 191:

INVENTORS GEORGE O. PUERNER JOSEPH L. KIRBY /FM ATTORNEY MEANS This invention relates to control devices; and more particularly, to a control device having a combination variable resistor and an electrical switch means.

Control devices are commonly used to regulate the speed of motors, vary the volume controls of radios and televisions, etc. Generally speaking, such devices utilize a variable resistor wherein electrical contacts slide over a resistance path. In some cases, such devices also include an on-off switch.

The present invention is concerned with such a device and has as one of its objects the provision of a variable resistorswitch combination control device.

Another object of the invention is the provision of a variable resistor-switch combination wherein an electrical shorting means is integral with an electrical resistance path.

Still another object of the invention is the provision of a variable resistor-switch combination wherein the electrical shorting means includes an electrically insulating material overlaying a portion of an electrical resistance path.

Yet another object of the invention is the provision of a variable resistor-switch combination wherein the electrical shorting means is an epoxy resin coated on an electrical resistance path.

A further object of the invention is the provision of a variable resistor-switch combination which includes electrical contact means having a single wiper means cooperating with an electrical resistance path.

Another object of the invention is the provision of a variable resistor-switch combination wherein electrical shorting means are integral with an electrical resistance path, the electrical resistance path including a portion of high conductivity and low resistance adjacent the electrical shorting means.

These and other objects of the invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein:

FIG. 1 is an exploded view of the control device of the invention;

FIG. 2 is a view taken along the line 2-2 of FIG. 1; and

FIG. 3 is an enlarged section taken along the line 3-3 of FIG. 2.

Generally speaking, the objects of the invention are accomplished by providing a variable resistor-switch combination comprising an electrical resistance path, electrical shorting means integral with the electrical resistance path, an electrical ground path, movable electrical contact means cooperating with the electrical resistance path, the electrical ground path, and the electrical shorting means, and electrical terminals electrically coupled to both of the paths. Additionally, the electrical resistance path includes a portion of high conductivity and low resistance disposed adjacent the electrical shorting means.

Referring now to the drawings control device includes a cup-shaped cover 12 closed by an electrically insulative board 14, the board 14 being connected to the cover through tabs 16 engaging slots 18 and then being bent over. A shaft means 20 is rotatably journaled in board 14 through aperture 22 and extends through cover 12 through aperture 24. Shaft means 20 includes a hub portion 26 which has a flange 28 carrying electrical contact means 30. Electrical contact means 30 include three wiper nibs 30', 30" and 30.

A variable resistance means 32 is carried by the electrically insulative board 14, the variable resistance means being clipped to the board through clip means 34 engaging apertures 36 and clip means 38 engaging apertures 40. As shown, clip means 38 also carries an electrical terminal 42. Also carried by the board 14 is an electrical ground path 43, the ground path being connected to the board through a clip means 44 engaging aperture 46. Clip means 44 has connected to it an electrical terminal 48.

Variable resistance means 32 includes a circular electrically insulative strip 50, a thin electrical resistive path 52 made of a suitable material such as a silver alloy, and a high conductivity low resistance portion 54. The high conductivity portion 54 includes a metal, such as copper, disposed between the clip 38 and the silver layer 52. An electrical shorting means 56 is formed integral with the variable resistance means 32 and includes a layer of electrically insulative material 58 disposed over the high conductivity portion 54. Alternately, if the high conductivity portion is not needed, electrically insulative material 58 may be coated directly over the silver layer 52. A suitable material for the electrically insulative material 58 would be an epoxy resin for example. The electrical shorting means in cooperation with the electrical contact means comprise an electrical on-off switching means for the control device.

In operation, wiper nibs 30" and 30" cooperate with the electrical ground path 43, while wiper nib 30' cooperates with the variable resistance means 32. Rotation of shaft means 20 could, for example, cause rotation of wiper nibs 30" from an area of high resistance A to an area of low resistance B, further rotation causing wiper nib 30 to engage the high conductivity portion 54, further rotation causing wiper nib 30 to engage the electrically insulative material 58 to thus break the circuit. Such operation would be especially useful in controlling the speed of a motor from one of low speed to high speed and turning the motor off and on. Or, conversely, the motor could be easily started in the high conductivity portion, and then adjusted. The use of a single wiper nib 30' along the variable resistive means lowers the amount of resistance per area thus providing longer life to the resistance path 42 formed by the silver alloy.

What is claimed is:

I. In a control device, a variable resistor-switch combination comprising:

a. an electrical resistance path including in series relationship a portion of high resistance followed by a portion of low resistance followed by a portion of electrically insulative material,

b. an electrical ground path,

c. movable electrical contact means cooperating with said electrical resistance path, and

d. electrical terminals electrically coupled to both of said paths.

2. In a control device according to claim 1 wherein said electrical insulating material includes an electrically insulative material overlaying a portion of said electrical resistance path.

3. In a control device according to claim 2 wherein said electrically insulative material is an epoxy resin.

4. In a control device according to claim 1 wherein both said paths are substantially circular.

5. In a control device according to claim 1 wherein said electrical contact means includes a single wiper means cooperating'with said electrical resistance path.

6. In a control device according to claim 1 wherein said electrical resistance path is a silver alloy and said portion of high conductivity and low resistance is copper.

7. A control device comprising:

a. a cup-shaped cover, an electrically insulative board closing the same and a shaft means rotatably journaled in said board and extending through said cup-shaped cover,

b. an electrical resistance path carried by said board and substantially surrounding said shaft means,

c. an electrical ground path carried by said board and substantially surrounding said shaft means,

d. electrical terminals connected to said ground path and one end of said electrical resistance path,

c. said electrical resistance path including a high conductivity and low resistance portion disposed at its electrical terminal end,

1. a layer of electrically insulative material disposed over a portion of said high conductivity and low resistance portion, and

. electrical contact means carried by and substantially surrounding said shaft means, said electrical contact means including a single wiper means engaging said electrical resistance path and said electrically insulative material and a double wiper means engaging said electrical ground path. 

1. In a control device, a variable resistor-switch combination comprising: a. an electrical resistance path including in series relationship a portion of high resistance followed by a portion of low resistance followed by a portion of electrically insulative material, b. an electrical ground path, c. movable electrical contact means cooperating with said electrical resistance path, and d. electrical terminals electrically coupled to both of said paths.
 2. In a control device according to claim 1 wherein said electrical insulating material includes an electrically insulative material overlaying a portion of said electrical resistance path.
 3. In a control device according to claim 2 wherein said electrically insulative material is an epoxy resin.
 4. In a control device according to claim 1 wherein both said paths are substantially circular.
 5. In a control device according to claim 1 wherein said electrical contact means includes a single wiper means cooperating with said electrical resistance path.
 6. In a control device according to claim 1 wherein said electrical resistance path is a silver alloy and said portion of high conductivity and low resistance is copper.
 7. A control device comprising: a. a cup-shaped cover, an electrically insulative board closing the same and a shaft means rotatably journaled in said board and extending through said cup-shapeD cover, b. an electrical resistance path carried by said board and substantially surrounding said shaft means, c. an electrical ground path carried by said board and substantially surrounding said shaft means, d. electrical terminals connected to said ground path and one end of said electrical resistance path, e. said electrical resistance path including a high conductivity and low resistance portion disposed at its electrical terminal end, f. a layer of electrically insulative material disposed over a portion of said high conductivity and low resistance portion, and g. electrical contact means carried by and substantially surrounding said shaft means, said electrical contact means including a single wiper means engaging said electrical resistance path and said electrically insulative material and a double wiper means engaging said electrical ground path. 